static headspace (hs) dynamic headspace spray-and-trap (st) spme membrane inlet

Static Headspace (HS) Dynamic Headspace Spray-and-Trap (ST) SPME Membrane InletPurge-and-TrapExtraction Methods

Advantage : More sensitive than HSDrawback : 1. Foaming and slowness of the purging step 2. Large sample volume and long purging time (10~30 min)

Purge-and-Trap Method

Experimental AimTo construct an automated ST-GC system for on-line determination of dissolved VOCs in water.

Carboxen 1000Carboxen 10031/16Micro-sorbent Trap

Spray-and-Trap Device

Cleaning

Sampling

Mode A

Mode B

Injection

2. Amount of sample3. Amount of extraction gas that is sampled.Sensitivity of Mode A1. Sprying conditionA. Size of dropletB. Extraction gas flow rateC. Design of nozzleD. Introducing a limited amount of sample and extraction gasSensitivity of Mode A

Mode A VS. Mode BA

Purge-and-Trap Device

Analytical conditions for ST and PT

Recoveries of ST methodsRecovery =

DL, R.S.D, and R2 for BTEX

Chromatograms of ST-GC-ECDCHCl3CCl4CH2Br2CHCl=CCl2CHBrCl2CCl2=CCl2

Conclusion An automated spray-and-trap device was built in the laboratory.

The studied ST method was validated in comparison with classic PT: recoveries precision, and linearity.

The ST method shows a fast response to abrupt changes in sample quality, which makes it suitable for on-site monitoring of a water body.